CA2065076A1 - Gear pump with pressure balancing structure - Google Patents
Gear pump with pressure balancing structureInfo
- Publication number
- CA2065076A1 CA2065076A1 CA002065076A CA2065076A CA2065076A1 CA 2065076 A1 CA2065076 A1 CA 2065076A1 CA 002065076 A CA002065076 A CA 002065076A CA 2065076 A CA2065076 A CA 2065076A CA 2065076 A1 CA2065076 A1 CA 2065076A1
- Authority
- CA
- Canada
- Prior art keywords
- gears
- gear
- pump chamber
- internal surface
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/0042—Systems for the equilibration of forces acting on the machines or pump
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Rotary Pumps (AREA)
Abstract
60,680-012 GEAR PUMP WITH PRESSURE BALANCING STRUCTURE
ABSTRACT OF THE DISCLOSURE
A gear pump which includes a pressure balancing structure to ensure balanced pressure within the pump chamber during low flow operation is disclosed. A groove is formed in the casing internal surface throughout the entire axial length of the gears and supplies high pressure fluid to positions within the pump chamber which are at a high pressure during normal flow operation. This groove thus ensures that high pressure fluid will be at all locations within the pump chamber which are expected to have high pressure during normal pumping operation. Forces on the gear are as expected during low flow operation, and that the gears will not be forced in an undesirable direction.
ABSTRACT OF THE DISCLOSURE
A gear pump which includes a pressure balancing structure to ensure balanced pressure within the pump chamber during low flow operation is disclosed. A groove is formed in the casing internal surface throughout the entire axial length of the gears and supplies high pressure fluid to positions within the pump chamber which are at a high pressure during normal flow operation. This groove thus ensures that high pressure fluid will be at all locations within the pump chamber which are expected to have high pressure during normal pumping operation. Forces on the gear are as expected during low flow operation, and that the gears will not be forced in an undesirable direction.
Description
. ~ 2065076 60,680-012 GEAR PUMP WIT~ PR~U~ ~ALANCING STRUCTUR~
~AC~GRnUffD ~F TnE INVENTIQN
The present invention relates to structure for providing balanced pressure to a gear pump during reduced flow operation.
Gear pumps are well known and utili~ed in many industrial applications. When used in hydraulic systems gear pumps may be operable to move fluid from a sump to a high pressure user system. These gear pumps may be constantly driven. When it is not desired to have the pump move fluid, some means of reducing the fluid moved by the constalltly rotating gears is used. A valve typically restricts the inlet flow to the pump.
A known gear pump system is illustrated in Figure 1. Gear pump 20 consists of a pair of gears 22 and 24 mounted within casin~ 26.
Inte m al surface 28 is formed within casing 26 alld defines a pump chamber to receive gears 22 and 24.
Sump 29 supplies fluid through inlet 30 into the pump chamber, and gears 22 and 24 rotate within the chamber to move fluid - around their outer peripheries to outlet 32. Outlet 32 delivers the fluid through a pressure gage 34 and to a user system 36. A high pressure typically exists at outlet 32.
A force is applied to gears 22 and 24 from the high pressure fluid on the discharge side in a direction towards the inlet side. This force F directs the gears against the internal surface 28 of casing 26 in a direction generally perpendicular to the rotational axes of the gears and towards inlet 30. Due to force F, gears 22 and 24 contact 2~65076 60,680-012 internal surface 28 and material is removed from internal surface 28 until groove 38 is formed. Groove 38 is customized for the particular gears 22 and 24 and casing 26. The removal of material, or '`tracking in" occurs during initial use of the gear pump and ensures a close fit between the tips of gear teeth 35 and internal surface 28. Internal surface 28 is quite hard, and as gears 22 and 24 remove material to form groove 38, the tips of gear teeth 35 may also be removed.
Contact line 33 is shown for gear 24. The spaces between adjacent gear teeth 35 past contact line 33, and towards outlet 32, contain high pres~ure fluid. Thus, there is high pressure fluid at positions between a center line 39 of casing 26 and contact line 33.
Center line 39 could be def;ned as the intersection of a plane defined by the axes of gears 22 and 24, and internal surface 28. The high pressure fluid in the space between contact line 33 and center line 39 associated with gear 2~1 applies a force in a direction upwardly and to the right, as shown in Figure 1. This force balances a force on the opposed side of gear 24 which is forcing it downwardly and to the left as shown in Figure 1. Thus, the resultant force F on gear 24 is directly to the left as shown in Figure 1, or in a direction towards inlet 30. Mirrored forces are applied to gear 22.
Inlet valve 40 is mounted on inlet 30 and can be actuated to restrict the flow of fluid from sump 29 into pump chamber 28. This would occur when it is not desired to have fluid delivered to system 36t but it is still desired to supply a small amount of fluid for bearing lubrication to rotating gear6 22 and 24. This is known as "dry valve"
operation. In such cases valve 40 is moved to the position illustrated in Figure 2 and the flow into pump chamber 28 is restricted. At these low flow conditions a high vacuum is placed on inlet 30 which removes 2~6~076 60,680~0~2 dissolved air from the fluid in the system. Air bubbles fill the spaces between adjacent gear teeth.
As shown in Figure 2, the inter tooth space between center line 39 and contact line 33 now contains air rather than high pressure fluid. The air bubbles continue to rotate towards outlet 32 until they contact high pressure fluid, at which time they collapse. There is still high pressure fluid ad~acent outlet 32, forcing gear 24 downwardly and to the left, but there is no longer high pressure fluid directing a force upwardly and to the right as shown in this figure. Thus the resultant force F is now downwardly and slightly to the left from the rotational axis of gear 24 and upwardly and slightly to the left from the rotational axis of gear 22. Gears 22 and 24 now move in these directions and new tracking grooves 42 are formed. The tips of gear teeth 35 experience additional wear tracking in groove 42.
When the pump returns to normal operation, there is no longer contact between gear teeth 35 and the casing at positions near contact line 33. The gear teeth tips have been removed such that there is undesirable clearance between gear teeth 35 and bore 28 near contact line 33, and perhaps throughout the entire circumferential extent of internal surface 28. This causes undesirable leaking.
Operating the gear pump under conditions such as extremely high vehicle attitude or low fluid levels could also result in the above-described problem. These conditions could result in a temporary uncovering of the inlet line in the fluid reservoir. When this occurs, large volu~es of air could be introduced into the inlet causing a problem similar to the above-discussed problem.
206~076 60,680-01~
Another problem that occurs when air is in the spaces between gear teeth is that pressure balanced side plates may be forced into the gears, such tllat the side plates could be torn or smeared. The side plates are typically forced against the gears by discharge pressure on a side remote of the pump chamber. This force is balanced by t~e pressure from the pump fluid within the pump chamber. In the absence of such pressure the side plates may be forced against the gears by an unbalanced force which could damage the side plates.
SUMMARY OF T~E rNVENTION
In a disclosed embodiment of the present invention, a groove is formed in the casing over the majority of the axial length of the gear at circumferential locations at least between the outlet and the center line of the casing. This groove ensures that high pressure fluid is directed into inter teeth spaces on the inlet side of the center line during any low flow operation. This high pressure fluid balances tl~e forces from the high pressure fluid adjacent tlle outlet, and prevents the gears from being forced in an undesired direction. If the groove extended for less than the majority of axial length of the gears, sufficient fluid may not be supplied to balance the pressure. Further, the gears could bend along their length.
These and other objects and features of the present invention can be best understood from the following specification and drawings.
BRIFF DESCRIPTION OF T~E DRAWINGS
Figure 1 is a cross-sectional view of a prior art gear pump under normal operation.
2~65076 60,680-012 Figure 2 is a cross-sectional view of a prior art gear pump during low flow operation.
Figure 3 is a cross-sectional view of a gear pump according to the present invention.
Figure 4 is a cross-sectional view along line 4-4 as sho~n in Figure 3.
DETAILED DFSCRIPTION OF A PRFF~RRRD EMBODIMENT
Gear pump 45 as disclosed in the present application is ~llustrated in Figure 3. Gear pump 45 includes groove 46 extending from a downstream location 48 to an upstream location 50. Downstream location 48 is slightly beyond a radius X drawn from the rotational axis of each of gears 22 and 24 perpendicular to a plane defined by the respective axes of gears 22 and 24, and in a direction towards outlet 32. Upstream end 50 is slightly beyond the 90 position on gears 22 and 24, measured from line X, and in a direction opposed to the direction of rotation of gears 22 and 24. The position of upstream end 50 is selected such that it remains downstream of contact line 33 during rotation of gears 22 and 24.
As formed, casing 46 has a generally cylindrical inner periphery other than at groove 46. Groove 46 is formed in casing 26 through the entire axial length of gears 22 and 24. Ends 52 of casing 26 are formed at axial positions beyond gears 22 and 24. Ends 52 mount side pressure plates. Internal surface 28 of gear pump 45 includes a generally cylindrical portion for each gear 22 and 24. Ends 52 have an inner periphery 53 that is generally cylindrical, as do the portion of bores 28 which do not receive groove 46. A track similar to groove 38 may form with use, see Figure 1, however, as manufactured bore 28 is 206~076 60,680-012 As shown, valve 40 is .in a restricted flow position and air bubbles are found in the pump chamber adjacent to inlet 30. Groove 46 taps fluid from the pump chamber adjacent outlet 32 and into the inter tooth space ad3acent upstream end 50. Thus, pressurized fluid is in the inter tooth space towards the inlet, past casing center line 39. The forces on gears 22 and 24 are properly directed or controlled. As shown, force F is perpendicular to the plane defined by the rotational axes of gears 22 and 24 and in a direction towards inlet 30. Gears 22 and 24 form a "track in" groove 38 as disclosed with reference to Figure 1.
Groove 46 has a first depth adjacent downstream end 48 and remains re].atively constant to a location 54 approximately 45 from the above radius X. After location 54 the groove depth beg~ns to trail away to smaller dimensions until it finally ends at upstream end 50. In one embodiment of gear pump 45, the gear diameter was 2.54 inches, the gear was 2.27 inches in axial length, and the groove depth at upstream end 48 was .10 inches. Groove 46 tapered to 0 inches at upstream point 50.
Figure 4 shows groove 46 extending for the entire axial length of gear 35. As shown, ends 52 have inner peripheral surfaces 53 which support pressure plates 60, shown in phantom, to define an : enclosed pump chamber.
Casing 26 is formed as a casting with a cylindrical bore including end 52. Groove 46 is machined into the bore during final machining.
206~076 60,680-012 A preferred embodiment of the present invention has been disclosed, however, a person of ordinary skill in the art would reco~nize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied in order to determine the true scope and content of this invention.
~AC~GRnUffD ~F TnE INVENTIQN
The present invention relates to structure for providing balanced pressure to a gear pump during reduced flow operation.
Gear pumps are well known and utili~ed in many industrial applications. When used in hydraulic systems gear pumps may be operable to move fluid from a sump to a high pressure user system. These gear pumps may be constantly driven. When it is not desired to have the pump move fluid, some means of reducing the fluid moved by the constalltly rotating gears is used. A valve typically restricts the inlet flow to the pump.
A known gear pump system is illustrated in Figure 1. Gear pump 20 consists of a pair of gears 22 and 24 mounted within casin~ 26.
Inte m al surface 28 is formed within casing 26 alld defines a pump chamber to receive gears 22 and 24.
Sump 29 supplies fluid through inlet 30 into the pump chamber, and gears 22 and 24 rotate within the chamber to move fluid - around their outer peripheries to outlet 32. Outlet 32 delivers the fluid through a pressure gage 34 and to a user system 36. A high pressure typically exists at outlet 32.
A force is applied to gears 22 and 24 from the high pressure fluid on the discharge side in a direction towards the inlet side. This force F directs the gears against the internal surface 28 of casing 26 in a direction generally perpendicular to the rotational axes of the gears and towards inlet 30. Due to force F, gears 22 and 24 contact 2~65076 60,680-012 internal surface 28 and material is removed from internal surface 28 until groove 38 is formed. Groove 38 is customized for the particular gears 22 and 24 and casing 26. The removal of material, or '`tracking in" occurs during initial use of the gear pump and ensures a close fit between the tips of gear teeth 35 and internal surface 28. Internal surface 28 is quite hard, and as gears 22 and 24 remove material to form groove 38, the tips of gear teeth 35 may also be removed.
Contact line 33 is shown for gear 24. The spaces between adjacent gear teeth 35 past contact line 33, and towards outlet 32, contain high pres~ure fluid. Thus, there is high pressure fluid at positions between a center line 39 of casing 26 and contact line 33.
Center line 39 could be def;ned as the intersection of a plane defined by the axes of gears 22 and 24, and internal surface 28. The high pressure fluid in the space between contact line 33 and center line 39 associated with gear 2~1 applies a force in a direction upwardly and to the right, as shown in Figure 1. This force balances a force on the opposed side of gear 24 which is forcing it downwardly and to the left as shown in Figure 1. Thus, the resultant force F on gear 24 is directly to the left as shown in Figure 1, or in a direction towards inlet 30. Mirrored forces are applied to gear 22.
Inlet valve 40 is mounted on inlet 30 and can be actuated to restrict the flow of fluid from sump 29 into pump chamber 28. This would occur when it is not desired to have fluid delivered to system 36t but it is still desired to supply a small amount of fluid for bearing lubrication to rotating gear6 22 and 24. This is known as "dry valve"
operation. In such cases valve 40 is moved to the position illustrated in Figure 2 and the flow into pump chamber 28 is restricted. At these low flow conditions a high vacuum is placed on inlet 30 which removes 2~6~076 60,680~0~2 dissolved air from the fluid in the system. Air bubbles fill the spaces between adjacent gear teeth.
As shown in Figure 2, the inter tooth space between center line 39 and contact line 33 now contains air rather than high pressure fluid. The air bubbles continue to rotate towards outlet 32 until they contact high pressure fluid, at which time they collapse. There is still high pressure fluid ad~acent outlet 32, forcing gear 24 downwardly and to the left, but there is no longer high pressure fluid directing a force upwardly and to the right as shown in this figure. Thus the resultant force F is now downwardly and slightly to the left from the rotational axis of gear 24 and upwardly and slightly to the left from the rotational axis of gear 22. Gears 22 and 24 now move in these directions and new tracking grooves 42 are formed. The tips of gear teeth 35 experience additional wear tracking in groove 42.
When the pump returns to normal operation, there is no longer contact between gear teeth 35 and the casing at positions near contact line 33. The gear teeth tips have been removed such that there is undesirable clearance between gear teeth 35 and bore 28 near contact line 33, and perhaps throughout the entire circumferential extent of internal surface 28. This causes undesirable leaking.
Operating the gear pump under conditions such as extremely high vehicle attitude or low fluid levels could also result in the above-described problem. These conditions could result in a temporary uncovering of the inlet line in the fluid reservoir. When this occurs, large volu~es of air could be introduced into the inlet causing a problem similar to the above-discussed problem.
206~076 60,680-01~
Another problem that occurs when air is in the spaces between gear teeth is that pressure balanced side plates may be forced into the gears, such tllat the side plates could be torn or smeared. The side plates are typically forced against the gears by discharge pressure on a side remote of the pump chamber. This force is balanced by t~e pressure from the pump fluid within the pump chamber. In the absence of such pressure the side plates may be forced against the gears by an unbalanced force which could damage the side plates.
SUMMARY OF T~E rNVENTION
In a disclosed embodiment of the present invention, a groove is formed in the casing over the majority of the axial length of the gear at circumferential locations at least between the outlet and the center line of the casing. This groove ensures that high pressure fluid is directed into inter teeth spaces on the inlet side of the center line during any low flow operation. This high pressure fluid balances tl~e forces from the high pressure fluid adjacent tlle outlet, and prevents the gears from being forced in an undesired direction. If the groove extended for less than the majority of axial length of the gears, sufficient fluid may not be supplied to balance the pressure. Further, the gears could bend along their length.
These and other objects and features of the present invention can be best understood from the following specification and drawings.
BRIFF DESCRIPTION OF T~E DRAWINGS
Figure 1 is a cross-sectional view of a prior art gear pump under normal operation.
2~65076 60,680-012 Figure 2 is a cross-sectional view of a prior art gear pump during low flow operation.
Figure 3 is a cross-sectional view of a gear pump according to the present invention.
Figure 4 is a cross-sectional view along line 4-4 as sho~n in Figure 3.
DETAILED DFSCRIPTION OF A PRFF~RRRD EMBODIMENT
Gear pump 45 as disclosed in the present application is ~llustrated in Figure 3. Gear pump 45 includes groove 46 extending from a downstream location 48 to an upstream location 50. Downstream location 48 is slightly beyond a radius X drawn from the rotational axis of each of gears 22 and 24 perpendicular to a plane defined by the respective axes of gears 22 and 24, and in a direction towards outlet 32. Upstream end 50 is slightly beyond the 90 position on gears 22 and 24, measured from line X, and in a direction opposed to the direction of rotation of gears 22 and 24. The position of upstream end 50 is selected such that it remains downstream of contact line 33 during rotation of gears 22 and 24.
As formed, casing 46 has a generally cylindrical inner periphery other than at groove 46. Groove 46 is formed in casing 26 through the entire axial length of gears 22 and 24. Ends 52 of casing 26 are formed at axial positions beyond gears 22 and 24. Ends 52 mount side pressure plates. Internal surface 28 of gear pump 45 includes a generally cylindrical portion for each gear 22 and 24. Ends 52 have an inner periphery 53 that is generally cylindrical, as do the portion of bores 28 which do not receive groove 46. A track similar to groove 38 may form with use, see Figure 1, however, as manufactured bore 28 is 206~076 60,680-012 As shown, valve 40 is .in a restricted flow position and air bubbles are found in the pump chamber adjacent to inlet 30. Groove 46 taps fluid from the pump chamber adjacent outlet 32 and into the inter tooth space ad3acent upstream end 50. Thus, pressurized fluid is in the inter tooth space towards the inlet, past casing center line 39. The forces on gears 22 and 24 are properly directed or controlled. As shown, force F is perpendicular to the plane defined by the rotational axes of gears 22 and 24 and in a direction towards inlet 30. Gears 22 and 24 form a "track in" groove 38 as disclosed with reference to Figure 1.
Groove 46 has a first depth adjacent downstream end 48 and remains re].atively constant to a location 54 approximately 45 from the above radius X. After location 54 the groove depth beg~ns to trail away to smaller dimensions until it finally ends at upstream end 50. In one embodiment of gear pump 45, the gear diameter was 2.54 inches, the gear was 2.27 inches in axial length, and the groove depth at upstream end 48 was .10 inches. Groove 46 tapered to 0 inches at upstream point 50.
Figure 4 shows groove 46 extending for the entire axial length of gear 35. As shown, ends 52 have inner peripheral surfaces 53 which support pressure plates 60, shown in phantom, to define an : enclosed pump chamber.
Casing 26 is formed as a casting with a cylindrical bore including end 52. Groove 46 is machined into the bore during final machining.
206~076 60,680-012 A preferred embodiment of the present invention has been disclosed, however, a person of ordinary skill in the art would reco~nize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied in order to determine the true scope and content of this invention.
Claims (15)
1. A gear pump comprising:
a housing having an internal surface defining a pump chamber;
a pair of gears having teeth at radially outer positions and mounted within said pump chamber, each of said gears being rotatable about an axis, said axes of said pair of gears extending parallel to each other and defining a plane, and each of said gears extending through a respective axial distance;
an inlet extending into said pump chamber on one side of said plane, and an outlet extending out of said pump chamber on an opposed side of said plane, said gears meshing and being driveable to move fluid from said inlet to said outlet; and said internal surface around each of said gears being such that said gear teeth are spaced from said internal surface in a region extending between at least 45 to 90° from a radius drawn from said axis of said gears perpendicular to said plane, in a direction towards said outlet, the angle being measured moving away from said outlet along said internal surface, said gear teeth being spaced from said internal surface in said region over the majority of said axial length.
a housing having an internal surface defining a pump chamber;
a pair of gears having teeth at radially outer positions and mounted within said pump chamber, each of said gears being rotatable about an axis, said axes of said pair of gears extending parallel to each other and defining a plane, and each of said gears extending through a respective axial distance;
an inlet extending into said pump chamber on one side of said plane, and an outlet extending out of said pump chamber on an opposed side of said plane, said gears meshing and being driveable to move fluid from said inlet to said outlet; and said internal surface around each of said gears being such that said gear teeth are spaced from said internal surface in a region extending between at least 45 to 90° from a radius drawn from said axis of said gears perpendicular to said plane, in a direction towards said outlet, the angle being measured moving away from said outlet along said internal surface, said gear teeth being spaced from said internal surface in said region over the majority of said axial length.
2. A gear pump as recited in claim 1, wherein said gear teeth are spaced from said internal surface in said region over the entirety of said axial length.
3. A gear pump as recited in claim 2, wherein said region extends from a relatively small negative angle to an angle slightly above 90° measured from said radius.
60,680-012
60,680-012
4. A gear pump as recited in claim 3, wherein said region is such that a clearance between said internal surface and said gear teeth remains essentially equal from the beginning of said region to approximately 45° measured from said radius, and then begins trailing off such that said gear teeth effectively contact said internal surface at an angle slightly over 90°.
5. A gear pump as recited in claim 4, wherein a valve is positioned on said inlet and is operable to restrict flow into said inlet.
6. A gear pump as recited in claim 1, wherein a valve is positioned on said inlet and is operable to restrict flow into said inlet.
60,680-012
60,680-012
7. A gear pump comprising:
a casing defining a pump chamber at an internal surface, a pair of gears being mounted within said pump chamber and rotatable about respective rotational axes, said respective rotational axes extending parallel to each other, each of said gears extending for a axial distance along its respective axis, and each of said gears having teeth at an outer periphery, said teeth of said respective gears meshing at locations spaced between their respective rotational axes;
an inlet extending into said pump chamber on one side of a plane defined by said respective rotational axes, an outlet extending out of said pump chamber on the opposed side of said plane;
center lines of said casing associated with each of said gears are defined as the intersection line between said plane and said internal surface; and grooves associated with each of said gears formed in said internal surface such that a clearance is provided between said gear teeth and said internal surface extending from a position adjacent said outlet to a position spaced on the inlet side of said center lines, said grooves extending for the majority of said axial length of each said gear.
a casing defining a pump chamber at an internal surface, a pair of gears being mounted within said pump chamber and rotatable about respective rotational axes, said respective rotational axes extending parallel to each other, each of said gears extending for a axial distance along its respective axis, and each of said gears having teeth at an outer periphery, said teeth of said respective gears meshing at locations spaced between their respective rotational axes;
an inlet extending into said pump chamber on one side of a plane defined by said respective rotational axes, an outlet extending out of said pump chamber on the opposed side of said plane;
center lines of said casing associated with each of said gears are defined as the intersection line between said plane and said internal surface; and grooves associated with each of said gears formed in said internal surface such that a clearance is provided between said gear teeth and said internal surface extending from a position adjacent said outlet to a position spaced on the inlet side of said center lines, said grooves extending for the majority of said axial length of each said gear.
8. A gear pump as recited in claim 7, wherein said groove extends for the entire axial length of each said gear.
9. A gear pump as recited in claim 7, wherein said inlet includes a valve operable to restrict flow into said pump chamber.
60,680-012
60,680-012
10. A gear pump as recited in claim 9, wherein said groove defines a casing inner periphery spaced a first distance from a respective rotational axis of an associated one of said gears near said outlet and spaced by a second distance near said center line, said first distance being greater than said second distance.
11. A gear pump as recited in claim 10, wherein the ratio of said first distance to the gear diameter is less than 1:20.
12. A gear pump comprising:
a casing having an internal surface defining a pump chamber, said pump chamber being formed of two pump chamber halves, each of said pump chamber halves defined by generally cylindrical surface portions on said internal surface centered about respective axes at a radial distance;
a pair of gears, with one of said gears being mounted in each of said pump chamber halves, said gears being rotatable about said respective axes, said gears having gear teeth at their outer peripheries and said gear teeth of said respective gears meshing at locations between said axes; and an inlet extending into said pump chamber on one side of a plane defined by said axes, an outlet extending out of said pump chamber on the opposed side of said plane, said plane intersecting said casing to define center lines, said pump chamber halves being configured such that said internal surface is non-cylindrical and at a distance away from said axes greater than said radial distance in a region beginning near said center line and moving in a direction towards said outlet, said region extending over the majority of the axial length of said gears to define a clearance.
60,680-012
a casing having an internal surface defining a pump chamber, said pump chamber being formed of two pump chamber halves, each of said pump chamber halves defined by generally cylindrical surface portions on said internal surface centered about respective axes at a radial distance;
a pair of gears, with one of said gears being mounted in each of said pump chamber halves, said gears being rotatable about said respective axes, said gears having gear teeth at their outer peripheries and said gear teeth of said respective gears meshing at locations between said axes; and an inlet extending into said pump chamber on one side of a plane defined by said axes, an outlet extending out of said pump chamber on the opposed side of said plane, said plane intersecting said casing to define center lines, said pump chamber halves being configured such that said internal surface is non-cylindrical and at a distance away from said axes greater than said radial distance in a region beginning near said center line and moving in a direction towards said outlet, said region extending over the majority of the axial length of said gears to define a clearance.
60,680-012
13. A gear pump as recited in claim 12, wherein said clearance having a downstream end spaced further from said axes than a nominal inner periphery of said pump chamber by a first distance and said gears having a diameter, the ratio of said first distance to said gear diameter being less than 1:20.
14. A gear pump as recited in claim 13, wherein said groove extends for the entire axial length of said gears.
15. A gear pump as recited in claim 14, wherein said internal surface extends inwardly at positions axially beyond each end of said gears, and defines a surface at said radial distance.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US684,618 | 1991-04-12 | ||
| US07/684,618 US5145349A (en) | 1991-04-12 | 1991-04-12 | Gear pump with pressure balancing structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2065076A1 true CA2065076A1 (en) | 1992-10-13 |
Family
ID=24748816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002065076A Abandoned CA2065076A1 (en) | 1991-04-12 | 1992-04-03 | Gear pump with pressure balancing structure |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US5145349A (en) |
| CA (1) | CA2065076A1 (en) |
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| US5403173A (en) * | 1994-03-08 | 1995-04-04 | Alliedsignal Inc. | Housing for intermeshing gear pump |
| GB2312476B (en) * | 1996-04-24 | 1999-12-08 | Sauer Sundstrand Ltd | Pressure balance control in gear pumps |
| US6123533A (en) * | 1997-04-22 | 2000-09-26 | Dana Corporation | Cavitation-free gear pump |
| HU222978B1 (en) * | 1998-10-01 | 2004-01-28 | Dow Global Technologies Inc. | Gear pump |
| US6254367B1 (en) * | 1998-11-02 | 2001-07-03 | Samuel Orrin Seiling | High viscosity product pumping method and apparatus |
| ES2174689B1 (en) * | 1999-11-18 | 2003-10-01 | Construcciones Mecanicas Pedro | PERFECTED BLOWING EQUIPMENT AND A CONSTRUCTION SYSTEM OF THE SAME. |
| DE10018348A1 (en) * | 2000-04-13 | 2001-10-25 | Bosch Gmbh Robert | Gearwheel pump for high pressure fuel pump has housing with gear wheels and groove having first and second sections with different spacing at bottom from tooth tips producing narrow gap for better pump action |
| EP1540184B1 (en) * | 2002-06-03 | 2015-04-29 | M&M Technologies, Inc. | Gear pump |
| US7527053B2 (en) | 2003-08-04 | 2009-05-05 | Cardinal Health 203, Inc. | Method and apparatus for attenuating compressor noise |
| US8156937B2 (en) | 2003-08-04 | 2012-04-17 | Carefusion 203, Inc. | Portable ventilator system |
| US8118024B2 (en) | 2003-08-04 | 2012-02-21 | Carefusion 203, Inc. | Mechanical ventilation system utilizing bias valve |
| US7607437B2 (en) | 2003-08-04 | 2009-10-27 | Cardinal Health 203, Inc. | Compressor control system and method for a portable ventilator |
| ES2592262T3 (en) | 2003-08-04 | 2016-11-29 | Carefusion 203, Inc. | Portable respirator system |
| US20050095160A1 (en) * | 2003-10-29 | 2005-05-05 | Heng-I Lin | Pump |
| US7997885B2 (en) | 2007-12-03 | 2011-08-16 | Carefusion 303, Inc. | Roots-type blower reduced acoustic signature method and apparatus |
| US8888711B2 (en) | 2008-04-08 | 2014-11-18 | Carefusion 203, Inc. | Flow sensor |
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| US2624287A (en) * | 1949-10-08 | 1953-01-06 | Borg Warner | Gear pump |
| US2820416A (en) * | 1952-12-24 | 1958-01-21 | Borg Warner | Pressure loaded pump |
| US2871794A (en) * | 1953-06-01 | 1959-02-03 | Roper Ind Inc | Gear pump or fluid motor |
| US3221663A (en) * | 1964-05-20 | 1965-12-07 | Chandler Evans Inc | Wash flow bearing system |
| US3474736A (en) * | 1967-12-27 | 1969-10-28 | Koehring Co | Pressure loaded gear pump |
| US3528756A (en) * | 1968-12-04 | 1970-09-15 | Borg Warner | Pressure loaded pump |
| GB1355957A (en) * | 1970-08-01 | 1974-06-12 | Dowty Hydraulic Units Ltd | Rotary fluid-pressure machines |
| US4087216A (en) * | 1976-10-05 | 1978-05-02 | Permco, Inc. | Flow diverter pressure plate |
| SU1023137A1 (en) * | 1977-12-05 | 1983-06-15 | Государственный Всесоюзный Ордена Трудового Красного Знамени Научно-Исследовательский Технологический Институт Ремонта И Эксплуатации Машинно-Тракторного Парка | Method of preparing gear pumps with two end-face sealing plates fixed in axial direction |
| DE3005656A1 (en) * | 1980-02-15 | 1981-08-20 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Gear pump for vehicle hydraulic system - has meshing gears in housing with throttle in inlet and non-return valve in outlet connection |
| US4355964A (en) * | 1980-08-22 | 1982-10-26 | Caterpillar Tractor Co. | Gear pump having fluid deaeration capability |
| SU1263910A1 (en) * | 1985-04-01 | 1986-10-15 | Государственный Всесоюзный Ордена Трудового Красного Знамени Научно-Исследовательский Технологический Институт Ремонта И Эксплуатации Машинно-Тракторного Парка | Method for preparing gear pumps |
| DE3620792A1 (en) * | 1986-06-20 | 1987-12-23 | Wankel Gmbh | EXTERNAL ROTATION PISTON BLOWER |
-
1991
- 1991-04-12 US US07/684,618 patent/US5145349A/en not_active Expired - Lifetime
-
1992
- 1992-04-03 CA CA002065076A patent/CA2065076A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US5145349A (en) | 1992-09-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |